LYONS, Colo. » By air and by land, the rescue of hundreds of Coloradoans stranded by epic mountain flooding was accelerating as food and water supplies ran low, while thousands more were driven from their homes on the plains as debris-filled rivers became muddy seas inundating towns and farms miles from the Rockies.

For the first time since the harrowing mountain floods began Wednesday, Colorado got its first broad view of the devastation — and the reality of what is becoming a long-term disaster is setting in. The flooding has affected parts of a 4,500-square-mile area, almost the size of Connecticut.

National Guard choppers were evacuating 295 people — plus pets — from the mountain hamlet of Jamestown, which was isolated by flooding that scoured the canyon the town sits in.

Mike Smith, incident commander at Boulder Municipal Airport, said helicopters would continue flying in and out late into the night.

The outlook for anyone who’d rather stay is weeks without power, cellphone service, water or sewer.

“Essentially, what they were threatening us with is, ‘If you stay here, you may be here for a month,”’ said 79-year-old Dean Hollenbaugh, who was evacuated by Chinook helicopter from Jamestown, northwest of Boulder.

For those awaiting an airlift, Guardsmen dropped food, water and other supplies in Jamestown and other small towns in the winding, narrow canyons that dot the Rocky Mountain foothills.

Thousands of evacuees sought shelter in cities that were nearly surrounded by raging rivers spilling over their banks. 

One was Mary Hemme, 62, who displayed a pair of purple socks as she sat outside the Lifebridge Christian Church in Longmont. They’re a memento of the more than 30 hours she spent in an elementary school in the flood-stricken mountain town of Lyons. Many evacuees — eventually rescued by National Guard trucks — got socks because most of them had wet feet, Hemme said.

She recalled the sirens blared at 2:30 a.m. Wednesday.

“Mary we have to go, this place is flooding,” she recalled her friend Kristen Vincent saying as they clambered out of a trailer.

“And we stepped out of the trailer, onto the ground where the cars were parked, and it already like this, almost to our knees,” she said. “It wasn’t just sitting there. It was rushing at us.”

Soon the trailer, like others in the park where she was staying, was submerged.

Hemme said she walked up at hill a daybreak and surveyed the trailer park.  

“The most terrifying thing was when I climbed up on that cliff and looked down. It was the meanest, most — I mean, no wonder it carries cars like toys,” Hemme said. “I was so afraid that I was going to die, that water came so fast.” 

The dayslong rush of water from higher ground has killed four people and turned towns on Colorado’s expansive eastern plains into muddy swamps. Crews used inflatable boats to rescue families and pets from stranded farmhouses. Some evacuees on horseback had to be escorted to safe ground.

Boulder County officials said Friday night that the number of people unaccounted for had risen to 172, according to local television and newspaper reports. The officials said earlier that the unaccounted for figure doesn’t necessarily represent missing people.

“It means we haven’t heard back from them,” county spokesman James Burrus said.

The city of Boulder reported late Friday that the rushing waters had caused “a significant breach in its main wastewater pipeline” to the treatment plant, but officials said it would not affect drinking water.

Near Greeley, some 35 miles east of the foothills, broad swaths of farmland had become lakes, and hundreds of roads were closed or damaged by floodwaters. A 70-mile stretch of Interstate 25 was closed from Denver to the Wyoming line.

Rocky Mountain National Park closed Friday, its visitors forced to leave via the 60-mile Trail Ridge Road to the west side of the Rockies.

It will be weeks, if not months, before a semblance of normalcy returns to Lyons, a gateway community to the park. The town, surrounded by sandstone cliffs whose color was reflected in the raging St. Vrain River, consisted of six islands Friday as residents barbecued their food before it spoiled. Several people set up a tent camp on a hill.

Some 2,500 residents were being evacuated from Lyons, but Hilary Clark was left walking around her neighborhood Friday.

Two bridges that led into the area were washed away. Unlike other parts of Lyons that had been reached by the National Guard in high clearance trucks, no such help had arrived for Clark.

“We’re surviving on what we got,” she said. “Some of us have ponds in our backyard and we’re using that water and boiling it.”

Boulder County Sheriff Joe Pelle said recovery would be long and expensive — similar to wildfires the state is more familiar with.

“Please be patient. This is an unprecedented event,” Pelle said.

Neary reported from Longmont. Associated Press writers David Martin in Boulder, Mead Gruver in Fort Collins, and Colleen Slevin and Thomas Peipert in Denver contributed to this report.